Apparatus and method for generating directional sound

Abstract

An apparatus for generating directional sound is provided. By using a time-variant beam pattern, the apparatus may generate constant direct waves in a listening area and may vary reflected waves followed by the direct waves according to time. The apparatus may convolute the time-variant beam pattern with a sound signal, may process an acoustic signal, which may be obtained through convolution, into a multi-channel signal, and may amplify and output the multi-channel signal.

What is claimed is: 
     
       1. An apparatus for generating directional sound, comprising:
 A beam pattern generator configured to generate a beam pattern varying according to time which maintains a magnitude of a direct sound wave and reduces according to time a magnitude of a reflected sound wave; 
 an operation device configured to convolute the generated beam pattern with an input sound source signal to generate an acoustic signal through the convolution; and process the acoustic signal into a multi-channel signal; and 
 a speaker array configured to output the multi-channel signal. 
 
     
     
       2. The apparatus of  claim 1 , wherein the beam pattern generator is further configured to generate, as the time-variant beam pattern, a beam pattern comprising an attenuation rate dependent on a distance. 
     
     
       3. The apparatus of  claim 1 , wherein the beam pattern generator is further configured to generate, as the time-variant beam pattern, beam patterns comprising the same sound pressure at a preset listening position, such that a direct wave comprises a magnitude independent of time. 
     
     
       4. The apparatus of  claim 1 , wherein the beam pattern generator comprises:
 a beam pattern storage configured to store at least two beam patterns comprising different focusing distances; and 
 a beam pattern selector configured to, select different beam patterns at each time interval from the stored beam patterns and output the selected beam patterns. 
 
     
     
       5. The apparatus of  claim 1 , wherein the beam pattern generator comprises:
 a storage configured to store at least two beam patterns comprising different focusing distances; and 
 a beam pattern synthesizer configured to select at least two beam patterns from the beam patterns stored in the storage, assign different weights to the selected beam patterns at each time interval, respectively, synthesize the beam patterns comprising different weights, and output the synthesized beam pattern. 
 
     
     
       6. The apparatus of  claim 5 , wherein a sum of the weights assigned to the selected beam pattern is 1. 
     
     
       7. A method of generating a directional sound, the comprising:
 generating a beam pattern varying according to time which maintains a magnitude of a direct sound wave and reduces according to time a magnitude of a reflected sound wave; performing a convolution on the generated beam pattern with an input sound source signal to generate an acoustic signal obtained through the convolution; 
 processing the generated acoustic signal into a multi-channel signal; and outputting the multi-channel signal. 
 
     
     
       8. The method of  claim 7 , wherein the time-variant beam pattern comprises a beam pattern comprising an attenuation rate dependent on a distance. 
     
     
       9. The method of  claim 7 , wherein the time-variant beam pattern comprises a beam pattern comprising the same sound pressure at a preset listening position, such that a direct wave comprises a magnitude independent of time. 
     
     
       10. The method of  claim 7 , wherein the generating of the beam pattern comprises:
 selecting different beam patterns from pre-stored beam patterns, the pre-stored beam patterns comprising different focusing distances, at each time interval; and 
 outputting the selected beam patterns. 
 
     
     
       11. The method of  claim 7 , wherein the generating of the beam pattern comprises:
 selecting at least two beam patterns from pre-stored beam patterns; 
 respectively assigning different weights to the selected beam patterns at each time interval; 
 synthesizing the beam patterns comprising different weights; and 
 outputting the synthesized beam pattern. 
 
     
     
       12. The method of  claim 11 , wherein a sum of the weights assigned to the selected beam pattern is 1. 
     
     
       13. A non-transitory computer-readable storage medium having stored therein program instructions to cause a processor to execute a method for an apparatus for generating directional sound, comprising:
 generating a beam pattern varying according to time which maintains a magnitude of a direct sound wave and reduces according to time a magnitude of a reflected sound wave; performing a convolution on the generated beam pattern with an input sound source signal to generate an acoustic signal obtained through the convolution; 
 processing the generated acoustic signal into a multi-channel signal; and outputting the multi-channel signal. 
 
     
     
       14. An apparatus for generating directional sound, comprising:
 a beam pattern generator configured to generate a beam pattern varying according to time which maintains a magnitude of a direct sound wave and reduces according to time a magnitude of a reflected sound wave; 
 An operation device, comprising: a convolution engine configured to convolute the generated beam pattern with an input sound source signal to generate an acoustic signal through the convolution; and a multi-channel amplifier configured to process the acoustic signal into a multi-channel signal; and a speaker array configured to output the multi-channel signal. 
 
     
     
       15. The apparatus of  claim 4 , wherein the focusing distance comprises a distance between a target position, on which sound energy is focused, and a center of the speaker array. 
     
     
       16. The apparatus of  claim 1 , wherein the beam pattern generator is configured to store beam patterns, which are calculated and normalized in advance, in an optional storage of the beam pattern generator, and read an individual beam pattern at each time interval. 
     
     
       17. The apparatus of  claim 16 , wherein the operation device is configured to update the convolution of the generated beam pattern with the input sound source signal at each time interval in the beam pattern generator, with a sound source signal in real time. 
     
     
       18. The apparatus of  claim 1 , wherein the beam pattern generator generates two beam patterns having different attenuation rates according to distance such that when they are applied to two sound pulses, direct waves of two response beam patterns are the same but reflected waves of the two response beam patterns are different due to the difference in attenuation rate of the two beam patterns. 
     
     
       19. The apparatus of  claim 1 , wherein the beam pattern varying according to time maintains the magnitude of a direct sound wave and simultaneously reduces the magnitude of the reflected sound wave over time.